Environmentally compatible laundry detergent

ABSTRACT

Laundry detergents wherein the active surfactant ingredients have the formula

United States Patent [191 Little et al.

[ ENVIRONMENTALLY COMPATIBLE LAUNDRY DETERGENT [75] Inventors: John C. Little, Danville, Calif;

Arthur S. Teot; Robert F. Harris, both of Midland, Mich.

[73] Assignee: The Dow Chemical Company,

Midland, Mich.

[22] Filed: May 15, 1972 [21] Appl. No.: 253,326

[52] US. Cl 252/527, 252/DIG, 1, 252/546, 260/404 [51] Int. Cl. Clld 3/075, Cl ld 3/30, C1 1d 3/08 [58] Field of Search 252/527, DIG. l, 546; 260/404 [56] References Cited UNITED STATES PATENTS 3,332,874 12/1965 Coward et al. 252/539 FOREIGN PATENTS OR APPLICATIONS 456,517 11/1936 Great Britain 252/546 June 25, 1974 1,169,496 11/1969 Great Britain 2,014,084 4/1970 France 2,042,793 2/1971 France Primary Examiner-l-lerbert B. Guynn Assistant Examiner--Edith L. Rollins Attorney, Agent, or FirmChessie E. Rehberg [5 7] ABSTRACT Laundry detergents wherein the active surfactant ingredients have the fonnula RO-(CH CH O)n-(CH ),--CHR'COOM 16 Claims, No Drawings ENVIRONMENTALLY COMPATIBLE LAUNDRY DETERGENT BACKGROUND OF THE INVENTION As a practical matter, most present commercial laundry detergents require large amounts of builders to be effective. The most effective and widely used builders are the phosphates. Now that phosphate builders are being restricted in many localities because of the environmental damage attributed to them, a widespread search has been launched for detergents that can be adequately built with phosphate-free builders.

The active surfactants used in the present invention include known compounds that have been used or recommended for use in shampoos, cosmetics, textile desizers, wool scouring agents, and the like (Felletschin, J. Soc. Cosmetic Chemists, 15, 250 (1964); Detergents for the Textile Industry, Technical Bulletin, Sandoz, lnc.; U.S. Pat. No. 2,183,853, British Pat. Nos. 926,898 and 793,113; French Pat. Nos. 2,014,084 and 2,042,793; Swiss Pat. No. 499,617; Chem-Y Technical Bulletins E-401, -402 and -403, and Lauryl (poly-1- oxypropene)oxaethane Carboxylic Acids, Fabriek van Chemische Produkten N.V., Noordstraat 49, Bodegraven, Holland).

The polyethoxylated fatty alcohols, RO(CH CH O)- ,,H, which may be regarded as the parents of the present surfactants, have been extensively studied. It has been noted that their most active members are those in which the fatty alcohol component, ROH, is near the lower end of the series, i.e., in the range of C to C and that as the number of ethoxyl groups, n, is increased, the surfactancy increases up to a value of n of about 8-10, while above this value the surfactancy changes but little (Nonionic Surfactants, M. J. Schick, editor, Vol. 1, pp. 102-114 (1967)). The surfactants used in the present invention have been found to generally follow the same pattern when tested in the absence of builders.

SUMMARY OF THE INVENTION The invention is in the use as laundry detergents of phosphate-free built detergent compositions wherein the active surfactant ingredient has the formula DETAILED DESCRIPTION OF THE INVENTION The active surfactant ingredients of the laundry detergents of the invention are a well-known class of compounds and additional members of the class can be made by the methods used to make the known ones.

The R group in the above formula is preferably a fatty alcohol radical of 14-20 carbon atoms, such as palmityl, stearyl, oleyl, and the like, or mixtures thereof. Generally, the products made from mixtures are somewhat more effective than those made from a single pure fatty alcohol. In the preferred surfactants, n is 2-6, x is O and R is H. Also preferred are the linear primary alcohols, although secondary and/or branched alcohols may also be used.

The surfactants of the invention are compatible with the usual laundry detergent additives, such as bleaches, brighteners, anti-redeposition agents, foam regulators, fillers, granulating agents, etc. Their effectiveness is unexpectedly enhanced by the phosphate-free builders, such as the alkali metal borates, silicates and carbonates. Other useful builders include the alkali metal or ammonium carboxylates, e.g., the citrates. mellitates, diglycolates, oxydisuccinates, ethylenediaminetetracarboxylates, nitrilotriacetates, N-hydroxyethyliminodiacetates, acetamidonitrilodiacetate and the like. Other suitable builders include those disclosed in U.S. Pat. No. 3,308,067.

The most convenient procedure for making the active surfactants used in the invention comprises (1) condensing ethylene oxide with the long chain fatty alcohol and (2) capping the resulting polyglycol monoether with a carboxyalkyl group, such as carboxymethyl or l-carboxy-l-butyl. The capping is conveniently effected by reaction with the appropriate chloroor bromocarboxylic acid in the presence of alkali. Such reaction is ordinarily not complete; hence, the reaction product often contains minor amounts of uncapped polyglycol monoether. While methods are available for separating the uncapped material as well as for assuring essentially complete capping, they are usually tedious and expensive. Fortunately, it has been found that minor proportions of such uncapped material are not particularly harmful, and may even be advantageous, especially since they are less expensive than the capped material.

The practice of the invention is illustrated by the following tests and examples.

Detergency Evaluation Tests A number of standard tests were carried out to demonstrate the efficiencies of the new formulations. These tests are described below.

Terg-O-Tometer Test One liter of standard 150 ppm. hard water (2:1 calciumzmagnesium ions) is placed in each of 4 stainless steel beakers of a Terg-O-Tometer (U.S. Testing Co., Inc., Model 144) and heated to 120F. Standard soiled test swatches are prepared by soaking 5 X 5 inch pieces of the desired fabric (such as bleached and desized cotton, style S/400W, from Test Fabrics, Inc.) for a minimum of 10 minutes in a soiling solution made from mixing 30 g. of vacuum cleaner soil which passed through a 270 mesh standard screen with three liters of distilled water. Most of the water is removed by pressing between paper towels and drying is completed by placing for 10 minutes in a l lO-120F. forced-air oven. Three of the soiled swatches and one clean swatch for measuring anti-redeposition for each fabric being tested are placed in each test beaker along with the detergent being evaluated and the mixtures are agitated in the Terg-O-Tometer for 10 minutes at rpm. The swatches are then removed, rinsed first by hand in lukewarm tap water and then in the (cleaned) test beaker containing one liter of the standard hard water for 5 minutes at 100 rpm. This test evaluates the detergency on two or three fabrics simultaneously. These are cotton, 65/35 cotton-polyester blend and the same blend with a permanent press finish.

The swatches are then removed, partially dried between paper towels and then ironed dry usinga cotton pressing cloth. The degree of whiteness is'determined by reading the reflectance of the twice-folded swatch on a standardized Photovolt Corporation Reflectometer, Model 610, using a green tristimulus filter. The average of four readings of each test swatch is compared with that of swatches washed in a commercial detergent, Tide (T.M., Proctor & Gamble Co.) or lvory (T.M., Proctor and Gamble Co.) soap flakes.

Repetition of the above for 2 more cycles gives a 3- cycle detergency reading, which is the reflectance reading after the third cycle, usually compared with that of the standard. As a general rule, brightness differences in swatches having reflectometer readings within two units of one another cannot be distinguished by the human eye. The effects of optical brighteners in e.g., the commercial materials are practically eliminated in the reflectometer by the use of the light filter.

Launderometer Test In a series of detergency tests similar to those above, the efficacy of various conventional builders was evaluated, using a commercial laundry detergent (0.2 percent) as a comparison. Some of the tests were run in a 25 making the surfactant. In the tablesftlie suffactant is identified by R and n as shown in the above formula and was used at 0.04 percent concentration unless otherwise noted; the fabrics used were cotton, a 65/35 polyester/cotton blend or the same blend treated with a permanent press resin (P.P. Blend). The commercial detergent used for comparison was used at a concentration of 0.2 percent.

The builders used in Examples 1-15 (except Example 6 and 10) were as follows (all percentages are based on total wash water): B, consisted of Na CO 0.108 percent, Na SiO 5H O, 0.0432 percent, carboxymethyl cellulose, 0.002 percent; B consisted of sodium silicate sold under the trade name Silicate BW (ratio of SiO to Na O, 1.6), 0.1 percent (water-free basis), Na S0 0.058 percent and carboxymethyl cellulose, 0.002 percent.

In Examples 16-34, the sodium silicate used was sold under the trade name Silicate G (ratio of SiO /Na O,

3.2). The use of this silicate results in a lowered pH of the wash solution without any adverse effect on the cleaning performance.

In some examples the detergency 'wasfiiba'rd to that of the American Association of Textile Chemists and Colorists (AATCC) standard detergent. Its composition is as follows:

Sodium linear alkylsulfonate l4 Fatty alcohol ethoxylate 2.3 Soap 2.5

Na tripolyphosphate 48.0 Sodium silicate (SiO,/Na O=2.0 9.7 Sodium sulfate 15.4 Na CMC .25 7.85 Misc.

To illustrate the unexpected improvement in the detergency of surfactants having low proportions of oxyethylene groups (low values of n) in the molecule when RO(CH CH O),.-CH COONa built with silicate-based builders, the following examv 7 V We A-A H H2.

TABLE I 3-Cycle Reflectance Detergent Redeposition Ex. R n Machine Soil Fabric Tide 8, B Tide B. B2

1 C 8.3 Laund. Oily Cotton 58 58 83 85 85 2 C1245 5.8 Laund. Oily Cotton 60 61 60 83 85 85 3 Cu; 8 3 Terg. Dry Cotton 75 76 83 83 84 Blend 71 7] 68 79 80 8O 4 C1248 5.8 Terg. Dry Cotton 72 72 66 84 83 84 Blend 71 69 64 80 79 79 5 C 6.8 Terg. Oily Cotton 69 69 69 84 84 86 Blend 66 64 59 79 80 81 6 C 6.8 Terg. Oily Cotton 66 67 82 83 7 C 1.8 Laund. Oily Cotton 66 63 83 83 P.P. Blend 68 64 8 C 3.1 Laund. Oily Cotton 66 61 Blend 70 62 9 C15 3 Laund. Oily Cotton 66 62 Blend 70 61 10 C 6.8 Terg. Oily Cotton 73 71 90 91 a 4 cycles instead of 3.

Builder was same as B except that the sodium silicate was replaced with an equal amount of sodium tripolyphosphate l y lq i stea 9%.

Builder was same as Bf'i'c i that silicate was reduzd to 0.012% and sodium diglycolate (0.04%)

was added.

wherein R is a straight-chain alkyl group having the 65 ples were run. In this series, the fatty alcohol used to carbon content indicated in the table below where a range is shown. e.g.. C a commercial mixture of fatty alcohols of the indicated chain length was used in make the surfactants was a commercial mixture of C alcohols. The builder formulation was 8,, described above.

3,819,538 6 TABLE 11 In a similar series of experiments, the effect of varying the concentration of sodium carbonate was noted.

Effect of Builder B, on Third Cycle Reflectance of z 2 )n' 2 The formulation and use level were the same as in 5 Examples 16-19 except that the silicate was constant Third Cycle Reflectance P 1 h 2. 2.... 2, "WAN-21 ermdnem Press at 15 percent wh1le the carbonate varied as shown be- Average Cotton Blend Ex. No. Value ofn Unbuilt Built Unbuilt Built low,

11 10.5 68.8 51.5 4 1a 7.9 68.0 69.4 52.0 54.9 The followmg expenments show that the sodium car- 13 5.7 66.0 73.6 49.3 61.7 l 4 4.3 6L8 740 50.0 68'1 bonate used in the builder in the previous experiments 15 2.5 73.0 62.5

TABLE IV Third Cycle Reflectance 65/35 Dacron/Cotton pH Wash 65/35 Dacron/ Blend with Permanent Ex. No. Na CO Solution Cotton Cotton Blend Press Finish In another series of experiments, the proportion of can be replaced with sodium sesquicarbonate. The forsodium silicate (SiO /Na O 3.2) was varied. The acmulatlon was the same as in Examples 20-23 except tive surfactant was that of Example 14. The formulathat the Sesquicarbonate and silicate were as indicated.

tion was as follows:

Third Cycle Reflectance 65/35'Dacr6n/C6tton Blend with Sodium Sodium pH Wash 65/35/ Dacron Permanent Ex. No. Sesquicarbonate Silicate Solution Cotton Cotton Blend Press Finish Control 20 10.35 69.4 64.2 62.9 24 69 20 9.90 68.5 64.6 63.5 25 54 9.80 68.1 63.8 61.6 26 35 54 9.75 69.3 61.9 60.4

54% Na CO V 7 VA V Na ca, While the use of sodium carboxymethylcellulose as ig g fg l 'zgg (Na CMC) 54; an antideposition agent is conventional, the following Nil SiilCBlE as indicated experiments demonstrate that it is effective with the de- M2504 balance tergents of the invention. The formulation and use level were the same as in Example 17 except that the Na The use level was 2.0 g./l. CMC level was varied TABLE VI Third C cle Reflectance /35 Dacron! 65/35 Dacron/Cotton Blend with Ex. No. CMC Cotton Cotton Blend Permanent Press Finish A TABLE III Sodium n/ Ex. No. Silicate Cotton Cotton Blend with Permanent Press Finish The effectiveness of the detergents of the invention in water of widely varying hardness is illustrated by the following experiments. The formulation and use level were as in Example 17.

TABLE 'vn e TABLE viii Third Cycle Reflectance 65/35 Dacron/Cotton Blend with Permanent Ex. No. Surfactant, SHlM, Cotton Press Finish Control 75.6 68.8 35 l 20 50 77.3 68.4 36 IO 50 76.2 67.4 37 20 35 76.0 67.7 38 I 35 77.9 68.5 39 77.9 67.8 40 5 2O 76.] 6L8 TXKTCC standard at 2.0 gms./l ave. of two runs The following experiments show theuse of nitrilot riacetate (Na salt) NTA) as a builder. The surfactants Third Cycle Reflectance 65/35 Dacron/Cotton fatty alcohols and differed only in the number of oxy- Water Blend with Permanent ethylene groups, n, thereon. The pH of all the wash so- 1 (I) n n Hardness (ppm) Hess Fmsh lutions was 9.8. The formulation, used at a level of 2 31 50 74.6 6L3 g was 23-8 Sodium silicate sio,/Na,o 3.2 10% 34 300 73 62 1 20 Na CMC l NTA as indicated ""CuVMg is 2/]; calculated as ppm CuCO Na SO, balance TABLE IX Third C cle Reflectance 65/35 Dacron/Cotton n in the NTA Blend with Permanent Ex. No. Surfactant Concentration Cotton Press Finish Control" 68.5 71.6 -0 .3 7 9.81 42 4.3 70.0 66.0 43 5.7 35 69.6 65.6 44 7.9 35 67.2 65.2 45 4.3 69.0 69.5 4.3 20 67.l 62.8

The following experiments show the exceptional effectiveness of the iminoacetate-type builders with the active surfactants of the present invention. In these ex- The utility of Na mellitate as a builder is shown in the following experiments paralleling those shown in Table periments, the formulation consisted of the active in- IX. gredient (surfactant) of Example 14 in the indicated a- TABLEX Third C ycle Reflectance "'Tide 605% mi sing) 1.

were all derivatives of a commercial mixture of C C 9 Thefollowing series of experiments illustrate the effect of the length of the carbon chain of the fatty alcohe] used in making the surfactant.

The formulation used was Surfactant as indicated Sodium carbonate 54% Sodium silicate sio,/Na,o 3.2)

Na CMC 1 Sodium sulfate balance 10 ferred proportion being about 6-12 percentfThe balance is made up of conventional additives, fillers, moisture, etc.

While the alkali metal salts of the surfactant acids are preferred, the ammonium and amine salts are also effective. Suitable amines include the lower alkyl (e.g.,

methyl, ethyl and butyl) amines and the lower alkanolamines (e.g., ethanol-, propanoland butanolamines).

While the disclosed surfactants may be (and preferably are) the sole active surfactants in the detergents, minor amounts (up to about 20 percent of the total surfactant) of other surfactants may be included, e.g., soaps, alkyl sulfates or alkyl or alkaryl sulfonates.

We claim:

1. An environmentally compatible laundry detergent consisting essentially of l. as the active surfactant ingredient, a compound of the formula RO-(CH CH O),,(CH CHR,COOM

wherein R is the hydrocarbon chain of a fattyalcohol Third Cycle Reflectance Deviation from AATCC Standard Surfactant 65/35 Blend Ex. No. R n Conc., Cotton Dacron/Cotton P.P. Blend 52 12 1.8 20 -5.0 7.2 5.2 53 12 3.1 20 3.6 6.9 7.5 54 12-18 3.1 20 l.1 1.9 2.9 55 12-18 4.0 20 1.9 2.5 8.3 56 16-18 1.4 20 2.8 18.7 57 16-18 3.7 10 +4.3 4.5 -3.5 58 16-18 5.8 10 +3.3 8.6 7.6 59 16-18 8.0 10 04 12.3 l4.5 60 18 5.9 20 -1.9 -99 8.7 61 18 8.3 20 0.3 8.5 -l2.0 62 16-20 2.0 20 +2.4 5.2 6.9 63 16-20 4.3 20 +3.6 l.l l.8 64 16-20 4.3 10 +2.6 5.2 7.2 65 16-20 5.7 20 2.3 4.7 9.1 66 16-20 7.9 20 06 9.1 l4.4

Expt. not run Not only are the detergents free of phosphate builders but the active surfactants thereof are readily biodegradable, especially those made from straight-chain fatty alcohols. Those made from branched-chain synthetic fatty alcohols are less readily degraded. Moreover, all of them are less toxic to fish and animals than many of the present widely used commercial detergents.

While the above examples illustrate only a limited variety of nonphosphate builders, and show them only in a limited range of proportions, it is to be understood that any of such builders in any conventional proportion can be used in the present invention. For example, when using a precipitating builder, such as the combination of alkali metal silicate and alkali metal carbonate, the builder may suitably constitute about 50-95' of about 12 to 221515611 atoms, n is'anififgfzw 6, x is 0 or 1, R is H or lower alkyl and M is alkali metal, ammonium or amine radical, and

2. a substantially phosphate-free detergent builder.

2. The detergent of claim 1 wherein M is alkali metal. 3. The detergent araaira'i wherein lifis T-li m 4. The detergent of claim 1 wherein x is 0.

5. The detergent of claim 1 wherein R has about 14-20 carbon atoms.

6. The detergent of claim 1 wherein the builder is a mixture of alkali metal silicate and alkali metal carbonate.

7. The detergent of claim 5 wherein the weight ratio of silicate to carbonate is about 1:1 to about 1:10.

8. The detergent of claim 1 containing about 3-25 percent by weight of active surfactant.

9. The detergent of claim 1 containing about 50-95 percent by weight of builder.

10. The detergent of claim 6 wherein the carbonate is sesquicarbonate.

11. The detergent of claim 1 wherein the builder is an alkali metal salt of a polycarboxylic acid.

12. The detergent of claim 11 wherein the polycarboxylic acid is an aminopolycarboxylic acid.

16. The detergent of claim 1 consisting essentially of about 3-25 percent by weight of active surfactant and about 10-95 percent of builder, said builder consisting essentially of one or more alkali metal borates, silicates or carbonates, citrates, mellitates, diglycolates, oxydisuccinates, ethylene-diaminetetracarboxylates, nitrilotriacetates, N-hydroxy-ethyliminodiacetates, acetamidonitrilodiacetates or a mixture of two or more thereof. 

2. a substantially phosphate-free detergent builder.
 2. The detergent of claim 1 wherein M is alkali metal.
 3. The detergent of claim 1 wherein R1 is H.
 4. The detergent of claim 1 wherein x is
 0. 5. The detergent of claim 1 wherein R has about 14-20 carbon atoms.
 6. The detergent of claim 1 wherein the builder is a mixture of alkali metal silicate and alkali metal carbonate.
 7. The detergent of claim 5 wherein the weight ratio of silicate to carbonate is about 1:1 to about 1:10.
 8. The detergent of claim 1 containing about 3-25 percent by weight of active surfactant.
 9. The detergent of claim 1 containing about 50-95 percent by weight of builder.
 10. The detergent of claim 6 wherein the carbonate is sesquicarbonate.
 11. The detergent of claim 1 wherein the builder is an alkali metal salt of a polycarboxylic acid.
 12. The detergent of claim 11 wherein the polycarboxylic acid is an aminopolycarboxylic acid.
 13. The detergent of claim 11 wherein the polycarboxylic acid is citric, mellitic, diglycolic, oxydisuccinic, nitrilotriacetic, N-hydroxyethyliminodiacetic, ethylene-diaminetetraacetic or acetamidonitrilodiacetic acid.
 14. The detergent of claim 7 containing about 3-25 percent by weight of active surfactant and about 50-95 percent by weight of builder.
 15. The detergent of claim 13 containing abouT 3-25 percent by weight of active surfactant and about 10-50 percent by weight of builder.
 16. The detergent of claim 1 consisting essentially of about 3-25 percent by weight of active surfactant and about 10-95 percent of builder, said builder consisting essentially of one or more alkali metal borates, silicates or carbonates, citrates, mellitates, diglycolates, oxydisuccinates, ethylene-diaminetetracarboxylates, nitrilotriacetates, N-hydroxy-ethyliminodiacetates, acetamidonitrilodiacetates or a mixture of two or more thereof. 